<?
$username=$_GET['username'];
$importo=$_POST['amount'];
$db = new DBManager ( 'localhost', 'root', '', 'iumus' );
$query="SELECT saldo FROM utente WHERE username='".$username."';";
$result=$db->executeQuery ($query);
$row=mysql_fetch_array($result);
$saldo=$row['saldo'];
$query="UPDATE utente SET saldo=".$importo." WHERE username='".$username."';";
$result=$db->executeQuery ($query);
?>